scholarly journals Too important to tamper with: predation risk affects body mass and escape behaviour but not escape ability

2017 ◽  
Vol 31 (7) ◽  
pp. 1405-1417 ◽  
Author(s):  
Benjamin T. Walters ◽  
Tin Nok Natalie Cheng ◽  
Justin Doyle ◽  
Chistopher G. Guglielmo ◽  
Michael Clinchy ◽  
...  
Keyword(s):  
Predation Risk ◽  
Body Mass ◽  
Escape Behaviour

scholarly journals Does risk of predation influence population dynamics? Evidence from cyclic decline of snowshoe hares

1995 ◽  
Vol 22 (1) ◽  
pp. 115 ◽  
Author(s):  
D. S. Hik
Keyword(s):  
Predation Risk ◽  
Body Mass ◽  
Female Body ◽  
Population Decline ◽  
Control Area ◽  
High Rate ◽  
Food Treatment ◽  
Snowshoe Hares ◽  
Risk Of Predation ◽  
Female Body Mass

Like most heavily preyed-upon animals, snowshoe hares (Lepus americanus) have to balance conflicting demands of obtaining food at a high rate and avoiding predators. Adopting foraging behaviours to minimise predation risk may also lead to a decline in condition, and hence fecundity. Predictions of three hypotheses (condition constraint hypothesis, predator-avoidance constraint hypothesis, predation-sensitive foraging (PSF) hypothesis) were tested by comparing changes in the survival and condition of snowshoe hares on four experimental areas in winter during a cyclic peak and decline (1989–1993) near Kluane Lake, Yukon, Canada, where (i) predation risk was reduced by excluding terrestrial predators (FENCE), (ii) food supply was supplemented with rabbit chow ad libitum (FOOD), (iii) these two treatments were combined (FENCE+FOOD), and (iv) an unmanipulated CONTROL was used. Different pattems of survival and changes in body mass were observed in the presence and absence of terrestrial predators. On the CONTROL area, female body mass and fecundity declined, even though sufficient winter forage was apparently available in all years. A similar decrease in body mass was observed on the FOOD treatment, but only during the third year of the population decline. In contrast, female body mass remained high throughout the decline in the absence of terrestrial predators in the FENCE+FOOD and FENCE treatments. Winter survival declined on CONTROL and FENCE areas during the first year of the population decline (1991), but remained higher on FOOD until 1992 and FENCE+FOOD until 1993. These results generally supported the PSF hypothesis where terrestrial predators were present (CONTROL and FOOD grids). Where terrestrial predators were absent (FENCE and FENCE+FOOD), the results supported the alternative condition constraint hypothesis. The evidence suggests that a cascade of sublethal behavioural and physiological effects associated with increased predation risk contribute to the population decline and delayed recovery of cyclic low-phase populations of snowshoe hares.

Habitat as a source of intrapopulational variation of ornament size in Galápagos lava lizards (Microlophus albemarlensis complex)

2008 ◽  
Vol 29 (2) ◽  
pp. 278-283 ◽  
Author(s):  
Mark Jordan ◽  
Howard Snell ◽  
Jennifer Hollis ◽  
Paul Stone
Keyword(s):  
Predation Risk ◽  
Body Mass ◽  
Predator Avoidance ◽  
Habitat Structure ◽  
Predation Pressure ◽  
Residual Body ◽  
Galápagos Islands ◽  
Vegetative Cover ◽  
High Predation ◽  
Intrapopulational Variation

Abstract Gradients in habitat structure are expected to influence the outcome of selection on traits that contribute to communicative display. Galápagos lava lizards (Microlophus albemarlensis complex) on Isla Plaza Sur in the Galápagos Islands occur across a gradient of vegetative cover. Previous work in this population has shown that traits associated with predator avoidance are magnified in habitats with low vegetative cover. This pattern suggests that predation pressure differs by habitat and thus, may act to select against the elaboration of ornamentation. We measured the size of the chin patch, an ornament known to be used in intraspecific signaling, to test this hypothesis. The area of the chin patch was dependent on both snout-vent length and residual body mass. In contrast to expectation, males had larger chin patches in the sparsely vegetated habitat suggested to have high predation risk. This result raises questions about the presumed survival cost of ornament elaboration.

Effects of predation risk on the body mass regulation of growing wood mice

2020 ◽  
Vol 312 (2) ◽  
pp. 122-132
Author(s):  
R. I. Monarca ◽  
J. R. Speakman ◽  
M. L. Mathias
Keyword(s):  
Predation Risk ◽  
Body Mass ◽  
The Body ◽  
Wood Mice ◽  
Body Mass Regulation

scholarly journals Ferruginous Pygmy-owl (Glaucidium brasilianum) predation on a mobbing Fork-tailed Flycatcher (Tyrannus savana) in south-east Brazil

2007 ◽  
Vol 7 (2) ◽  
pp. 321-324 ◽  
Author(s):  
José Carlos Motta-Junior
Keyword(s):  
Predation Risk ◽  
Body Mass ◽  
Bird Species ◽  
Large Prey ◽  
Predation Event ◽  
Glaucidium Brasilianum

I observed, and documented in detail, Ferruginous Pygmy Owl (Glaucidium brasilianum) predation on a mobbing Fork-tailed Flycatcher (Tyrannus savanna) in south-east Brazil. Events described in this account are supported with original photos. In addition to the predation event, I list 12 mobbing bird species that were alarmed by the presence of this raptor in the study area, including Trochilidae (Eupetomena macroura), Formicariidae (Formicivora rufa), Tyrannidae (Camptostoma obsoletum, Elaenia cristata, E. flavogaster, E. chiriquensis, T. savana, Myiarchus tyrannulus), Turdidae (Turdus leucomelas, T. amaurochalinus, T. rufiventris) and Emberizidae (Coryphospingus cucullatus). The Fork-tailed Flycatcher may represent 35-76.8% of the pygmy-owl body mass (41-80 g), which supports early reports about the predation on relatively large prey by this owl species. Although most authors have suggested that mobbing birds are subject to a low predation risk, this report and others confirmed that these events are not negligible and can be deadly dangerous to the mobbers, and conversely profitable to the raptor.

scholarly journals Seasonal and Diurnal Body-Mass Fluctuations for two Nonhoarding Species of Parus in Sweden Modeled Using Path Analysis

The Auk ◽  
2003 ◽  
Vol 120 (3) ◽  
pp. 658-668
Author(s):  
Pekka T. Rintamäkt ◽  
Jon R. Stone ◽  
Arne Lundberg
Keyword(s):  
Path Analysis ◽  
Predation Risk ◽  
Body Mass ◽  
Great Tit ◽  
Energy Reserves ◽  
Blue Tit ◽  
Passerine Species ◽  
State Dependent ◽  
Mass Dependent ◽  
Winter Fattening

Abstract According to the hypothesis that has been invoked most frequently to explain seasonal fattening patterns for birds—the “adaptive winter-fattening hypothesis”—individuals respond to worsening foraging conditions by increasing body mass and energy reserves. Two hypotheses have been proposed equally frequently to explain daily weight gain patterns for birds: according to the “state-dependent foraging hypothesis,” energy reserves should be amassed early during the day, when starvation risk increases; according to the “mass-dependent predation-risk hypothesis,” mass gain should be delayed for as long as possible, to minimize predation risk. Those hypotheses have been tested previously, using statistical methods (e.g. multiple-regression analysis) that assume independence among environmental variables (e.g. photoperiod and temperature). We conducted path analyses that included four predictor variables (day-in-season, hour-in-day, mean daily temperature, and daily precipitation) to model body-mass fluctuations for two small, nonhoarding (noncaching) passerine species that inhabit central eastern Sweden. Data were partitioned hierarchically into species, age class, gender, and season subgroups. As reported in many small passerine species studies, body mass increased during the day and maximized at dusk; over seasons, body mass increased during autumn, maximized by midwinter, and declined toward breeding in spring. Path analysis models accounted for 9.5–49.9% (mean 26.3%) for Blue Tit (Parus caeruleus) body mass variance and 1.8–52.3% (mean 16.8%) for Great Tit (P. major) body mass variance; for both species, accountability was lowest for autumn (Blue Tit,12.2%; Great Tit, 7.3%), highest for winter (Blue Tit, 33.4%; Great Tit, 21.9%), and intermediate for spring (Blue Tit, 22.7%; Great Tit, 11.8%); for Blue Tits, it was greater for adults than for juveniles (33.2 and 21.7%); whereas negligible for Great Tits (15.9 and 17.3%) and slightly greater for males than for females (Blue Tit, 27.4 and 23.5%; Great Tit, 23.1 and 21.3%). Those results are consistent with predictions formulated on the basis of the adaptive winter-fattening, partially with state-dependent foraging, and, possibly, mass-dependent predation-risk hypothesies and reveal that body-mass fluctuations are associated to a greater extent with photoperiod than with temperature.

Loss of body mass under predation risk: cost of antipredatory behaviour or adaptive fit-for-escape?

2004 ◽  
Vol 67 (3) ◽  
pp. 511-521 ◽  
Author(s):  
Javier Pérez-Tris ◽  
José A. Dı́az ◽  
José Luis Tellerı́a
Keyword(s):  
Predation Risk ◽  
Body Mass ◽  
Antipredatory Behaviour ◽  
Risk Cost

scholarly journals Adaptation and constraint shape the evolution of growth patterns in passerine birds across the globe

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Vladimír Remeš ◽  
Beata Matysioková ◽  
Jakub Vrána
Keyword(s):  
Predation Risk ◽  
Clutch Size ◽  
Body Mass ◽  
Growth Rates ◽  
Nest Predation ◽  
Tail Length ◽  
Growth Patterns ◽  
Passerine Birds ◽  
Data Quality Control ◽  
Nest Height

Abstract Background Growth trajectories should be adapted to selective factors of each species’ environment. However, major shaping forces of growth and development are unclear, especially when studying several traits at once. Birds provide an ideal opportunity to analyze growth patterns across species due to there being enough available data. We tested the relative importance of nest predation risk, the number of care-givers, nest height, foraging substrate, clutch size, and latitude on growth patterns of passerine birds (Passeriformes) using phylogenetic comparative methods. Specifically, we studied the evolution of fledging time, average and peak growth rates, and relative development at fledging of body mass and tarsus, wing, and tail length. Results Using a comprehensive literature search and data quality control, we obtained data on growth in 231 species based on 295 populations. Species with long development in the nest grew slowly and had well-developed traits at fledging. Species breeding under high nest predation risk, building their nests close to the ground, and those living in northern temperate regions fledged early and grew fast, sometimes fledging with less developed body mass and traits critical for locomotion (tarsus, wing, and tail). On the other hand, the number of caring adults, clutch size, and species’ foraging substrate had very limited predictive value for growth patterns across passerine species. Conclusions Shortening of the nestling period was a primary means of accelerating development (in relation to nest predation, nest height, and latitude), sometimes supplemented by higher peak growth rates of body mass, tarsus, and wing (especially in relation to latitude). Overall growth patterns of passerines were adaptively tuned to nest predation risk and nest height, with northern temperate species having especially short nestling periods and fast growth rates of body mass, tarsus, and wing.

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